Alesis io2 USB sound card unresponsive after sleep

Hi All,

I've read similar questons about other USB audio devices so maybe someone has the solution to this.

Since a while (I could not tell what version os Mac OS X brought that to us), my Alesis IO2 (and also a Focusrite Saphire USB) gets unresponsive most of the times when my Mac Pro (5,1) is awaken from sleep. I have to unplug it and plug it in again to regain audio capabilities. This is very annoying.